copr: fix read_decimal multiply overflow panic (#6045)
copr: fix read_decimal multiply overflow panic (#6045)

Signed-off-by: TennyZhuang <3a103716d63d8ccb206f8201b2c2788f77394e58@gmail.com>
pingcap/tikv,pingcap/tikv,BusyJay/tikv,BusyJay/tikv,BusyJay/tikv,c4pt0r/tikv,BusyJay/tikv